Running on 7 cylinders w/o any codes?
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Drifting
Joined: Jul 2015
Posts: 31
Likes: 1
From: Winston-Salem NC
Running on 7 cylinders w/o any codes?
Guys,
Was driving the Discovery yesterday and got a terrible misfire, Ultraguage immediately started beeping and the Service Engine Soon light started flashing. Was about a mile from the house and was able to limp it home. Pedal to the floor I could only manage 15 mph. Pulled the codes P1300, 0303 and 0302, plugs and wires are 8k miles old. Talked to a friend who happens to be a master Rover tech and decided it was most likely a bad coil pack.
Spent today pulling the intake off, not too bad of a job and replacing the coil packs, did both as I am sure they were original. When I was taking the coil packs out I noticed one of them was broken, spark plug wire was down by the tranny and severely corroded. Could I have been running on 7 cylinders without any codes for the last 8k miles? looks like the coil was probably broken when the engine was installed. It was very dusty, I am sure it wasn't connected on my safari trip at Uwharri as everything got coated in dust that weekend. The part where the plug wire connects was full of dust/dirt. Put it all back together and my idle is much smoother and it feels like it has more power.
I just don't understand how I have not been getting any other codes if I have been driving a V7 not at V8. Was the second cylinder back on the driver's side if that would make a difference?
Was driving the Discovery yesterday and got a terrible misfire, Ultraguage immediately started beeping and the Service Engine Soon light started flashing. Was about a mile from the house and was able to limp it home. Pedal to the floor I could only manage 15 mph. Pulled the codes P1300, 0303 and 0302, plugs and wires are 8k miles old. Talked to a friend who happens to be a master Rover tech and decided it was most likely a bad coil pack.
Spent today pulling the intake off, not too bad of a job and replacing the coil packs, did both as I am sure they were original. When I was taking the coil packs out I noticed one of them was broken, spark plug wire was down by the tranny and severely corroded. Could I have been running on 7 cylinders without any codes for the last 8k miles? looks like the coil was probably broken when the engine was installed. It was very dusty, I am sure it wasn't connected on my safari trip at Uwharri as everything got coated in dust that weekend. The part where the plug wire connects was full of dust/dirt. Put it all back together and my idle is much smoother and it feels like it has more power.
I just don't understand how I have not been getting any other codes if I have been driving a V7 not at V8. Was the second cylinder back on the driver's side if that would make a difference?
Three Wheeling
Joined: Apr 2009
Posts: 68
Likes: 0
From: CT
i guess anything is possible, especially since you noticed a considerable change in the engine's overall character (smoother idle and more power). i know cars more and more rely on computers for diagnostics, etc. but still, they're not infallible.
Winching
Joined: May 2012
Posts: 676
Likes: 37
From: Wylie, TX
Guys,
Was driving the Discovery yesterday and got a terrible misfire, Ultraguage immediately started beeping and the Service Engine Soon light started flashing. Was about a mile from the house and was able to limp it home. Pedal to the floor I could only manage 15 mph. Pulled the codes P1300, 0303 and 0302, plugs and wires are 8k miles old. Talked to a friend who happens to be a master Rover tech and decided it was most likely a bad coil pack.
Spent today pulling the intake off, not too bad of a job and replacing the coil packs, did both as I am sure they were original. When I was taking the coil packs out I noticed one of them was broken, spark plug wire was down by the tranny and severely corroded. Could I have been running on 7 cylinders without any codes for the last 8k miles? looks like the coil was probably broken when the engine was installed. It was very dusty, I am sure it wasn't connected on my safari trip at Uwharri as everything got coated in dust that weekend. The part where the plug wire connects was full of dust/dirt. Put it all back together and my idle is much smoother and it feels like it has more power.
I just don't understand how I have not been getting any other codes if I have been driving a V7 not at V8. Was the second cylinder back on the driver's side if that would make a difference?
Was driving the Discovery yesterday and got a terrible misfire, Ultraguage immediately started beeping and the Service Engine Soon light started flashing. Was about a mile from the house and was able to limp it home. Pedal to the floor I could only manage 15 mph. Pulled the codes P1300, 0303 and 0302, plugs and wires are 8k miles old. Talked to a friend who happens to be a master Rover tech and decided it was most likely a bad coil pack.
Spent today pulling the intake off, not too bad of a job and replacing the coil packs, did both as I am sure they were original. When I was taking the coil packs out I noticed one of them was broken, spark plug wire was down by the tranny and severely corroded. Could I have been running on 7 cylinders without any codes for the last 8k miles? looks like the coil was probably broken when the engine was installed. It was very dusty, I am sure it wasn't connected on my safari trip at Uwharri as everything got coated in dust that weekend. The part where the plug wire connects was full of dust/dirt. Put it all back together and my idle is much smoother and it feels like it has more power.
I just don't understand how I have not been getting any other codes if I have been driving a V7 not at V8. Was the second cylinder back on the driver's side if that would make a difference?
Camel Trophy
Joined: Nov 2012
Posts: 3,717
Likes: 248
From: Longview, Texas
Jamie had another thread on the check engine light, though, and I think the point is why he would not have any codes when there was obviously a problem that should throw a code. I even recall that he swapped plug wires between plugs and didn't get a misfire or code. I am still surprised about that one.
I have an excursion (5.4) that wasn't running quite right but had no code. After a couple of weeks driving it that way I found that one of the coils (it has a coil on each plug) had come unplugged. Obviously, it had zero spark on that cylinder, yet it ran well enough and did not show a code. The only way I could get a code was when I pulled two coils at once.
But JamieB has the same setup as us all, and the slightest hiccup lights up my dash.
What determines a misfire? Isn't it the knock sensors?
I have an excursion (5.4) that wasn't running quite right but had no code. After a couple of weeks driving it that way I found that one of the coils (it has a coil on each plug) had come unplugged. Obviously, it had zero spark on that cylinder, yet it ran well enough and did not show a code. The only way I could get a code was when I pulled two coils at once.
But JamieB has the same setup as us all, and the slightest hiccup lights up my dash.
What determines a misfire? Isn't it the knock sensors?
Winching
Joined: May 2012
Posts: 676
Likes: 37
From: Wylie, TX
Charlie, yes, I was chasing my tail left and right with that misfire. Mine ended up being a single coil wire that had fried inside the connector to the coil. Mine was arcing enough to get fire at times and other times would throw the light (usually under a load).
Funny thing, my alternator light would flicker intermittently too. Seems when I replaced my wires, the alternator light stopped flickering. Go figure.
Funny thing, my alternator light would flicker intermittently too. Seems when I replaced my wires, the alternator light stopped flickering. Go figure.
Pro Wrench
Joined: Nov 2015
Posts: 1,935
Likes: 189
From: Coastal Georgia
Why/how no codes? Maybe all the ones and zeros didn't line up correctly.
Info on MF detection system:
......
Info on MF detection system:
Misfire detection
Due to increasing legislation, all new vehicles must be able to detect two specific levels of misfire.
Conditions
The ECM is able to carry out misfire detection as part of the OBD system using the following component parts:
l Flywheel reluctor adaptation.
l Calculation of engine roughness.
l Detection of excess emissions misfire.
l Detection of catalyst damaging misfire.
Function
The flywheel/ reluctor ring is divided into four segments 90° wide. The ECM misfire detection system uses information
generated by the CKP to determine crankshaft speed and position. If a misfire occurs, there will be an instantaneous
slight decrease in engine speed. The ECM misfire detection system is able to compare the length of time each 90°
segment takes and is therefore able to pinpoint the source of the misfire.
For the ECM misfire detection system to be calibrated for the tolerances of the reluctor tooth positions, the flywheel/
reluctor ring must be 'adapted' as follows:
l 1800 - 3000 rev/min = speed range 1.
l 3000 - 3800 rev/min = speed range 2.
l 3800 - 4600 rev/min = speed range 3.
l 4600 - 5400 rev/min = speed range 4.
The ECM carries out flywheel/ reluctor ring adaptions across all the above speed ranges and can be monitored by
TestBook. The test should be carried out as follows:
l Engine at normal operating temperature.
l Select second gear (for both automatic and manual transmission vehicles).
l Accelerate until engine rev limiter is operational.
l Release throttle smoothly to allow engine to decelerate throughout the speed ranges.
l Repeat process as necessary until all adaptations are complete.
Due to increasing legislation, all new vehicles must be able to detect two specific levels of misfire.
Conditions
The ECM is able to carry out misfire detection as part of the OBD system using the following component parts:
l Flywheel reluctor adaptation.
l Calculation of engine roughness.
l Detection of excess emissions misfire.
l Detection of catalyst damaging misfire.
Function
The flywheel/ reluctor ring is divided into four segments 90° wide. The ECM misfire detection system uses information
generated by the CKP to determine crankshaft speed and position. If a misfire occurs, there will be an instantaneous
slight decrease in engine speed. The ECM misfire detection system is able to compare the length of time each 90°
segment takes and is therefore able to pinpoint the source of the misfire.
For the ECM misfire detection system to be calibrated for the tolerances of the reluctor tooth positions, the flywheel/
reluctor ring must be 'adapted' as follows:
l 1800 - 3000 rev/min = speed range 1.
l 3000 - 3800 rev/min = speed range 2.
l 3800 - 4600 rev/min = speed range 3.
l 4600 - 5400 rev/min = speed range 4.
The ECM carries out flywheel/ reluctor ring adaptions across all the above speed ranges and can be monitored by
TestBook. The test should be carried out as follows:
l Engine at normal operating temperature.
l Select second gear (for both automatic and manual transmission vehicles).
l Accelerate until engine rev limiter is operational.
l Release throttle smoothly to allow engine to decelerate throughout the speed ranges.
l Repeat process as necessary until all adaptations are complete.
Camel Trophy
Joined: Nov 2012
Posts: 3,717
Likes: 248
From: Longview, Texas
Number9 you are a literal genius at finding technical info. Info aside, I am Really glad you are active in the forums.
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